In special applications there is a need for single cycle valves which need only perform a valve function once during their use. Such apparatus is employed in the refrigeration arts wherein precharged components of a refrigeration system are pressurized with a refrigerant at the factory, shipped and assembled at the site of use. Such precharged refrigeration units may include the evaporator unit, a compressor-condenser unit, and the conduit system utilized to interconnect these units. Coupling fittings are presently used with such precharged systems which employ diaphragms severed by piercing members wherein interconnecting of the coupling halves, usually by a nut, ruptures the diaphragm and permits fluid interconnection between the coupled parts.
Rupturable diaphragm couplings, commonly called "one-shot" couplings, are expensive to manufacture, requiring several machined components, and the fracturing of the diaphragms often results in loose fragments within the conduit system. The ruptured diaphragm often produces ragged and sharp edges, and the irregular flow orifices that may result produce restriction to fluid flow, and undesirable turbulence. "One-shot" couplings of the aforementioned type are shown in U.S. Pat. No. 2,933,333 and in the assignee's U.S. Pat. No. 3,202,442.
It is an object of the invention to provide a single cycle valve which may be used with precharged refrigeration systems, and the like, which is of economical construction and positive in operation, providing unrestricted fluid flow when the valve element has been opened.
Another object of the invention is to provide a single cycle valve of economical manufacture which is thermally operated wherein the external application of heat to the valve body releases a valve element from its seated condition, and wherein the released valve element is retained at a location which does not interfere with the fluid flow through the valve body.
Yet another object of the invention is to provide a single cycle valve of a sheet metal construction wherein the external application of heat releases a seated valve element from a valve chamber inlet port, and the valve chamber includes an outlet port including a projection having an arcuate surface which prevents the accidental seating of the released valve element in the outlet port to restrict fluid flow.
In the practice of the invention a pair of sheet metal components are soldered or brazed together in fluid tight connected relationship. Each component includes an enlarged bell portion and a tubular stem portion concentric with the bell portion. The bell portions of the parts are interconnected whereby the stems are in opposed coaxial relationship with respect to a chamber defined by the bell portions.
The interconnection of the stems with the chamber defines inlet and outlet ports, and a valve element is soldered with a low temperature fusible material within the inlet port. The application of external heat to the bell portion adjacent the valve element melts the fusible material causing the valve element to fall to the lower region of the valve chamber thereby permitting unrestricted fluid flow through the valve chamber and stems.
Preferably, the chamber outlet port includes a projection extending into the chamber having an arcuate surface which prevents seating of the valve element within the outlet port, and prevents the released valve element from accidentally restricting the valve against fluid flow therethrough.
The transverse dimension of the valve chamber is considerably greater than the transverse cross sectional dimension of the stem in which the valve element is originally sealed, whereby the release of the valve element permits the same to rest offset with respect to the flow path through the valve body.